So, 2004 XJR with 120K. Heat progressively goes away over the past few winters until it's cool this year. Not cold, mind you, but it just doesn't feel warm. If I put my hand in front of the air vents, it feels a little cooler than ambient, but as I stated, I'm not freezing to death when it's in the teens.

So, I keep reading all of these horror stories about clogged heater cores under the dash. ok. That must be the problem.

I got my indy to try to flush the cores. But that only worked for about the hour that it took to drive home. Next day back to the same.

Well, I picked up on those who were starting to explore the auxiliary water pump that is attached to the radiator. Well, that got me thinking. I can't tell you how many things I've replaced in the area of the radiator. All of the hoses, the expansion tank, repair to the windshield washer reservoir, etc. There is just so much heat up there.

So, on a whim I just decided to order the pump and replace it before verifying that the pump worked or not. After all, I can probably replace the thing in a couple of hours and I'm sure I'll have to replace it in the future anyway, so may as well be proactive.

Well damn if I don't have glorious, wonderful, melt your toes and face right off HEAT!!!!! Wow, I didn't think I'd ever get heat again.

So, give thought to replacing that little pump before you spend a lot of $$$ replacing the heater cores!

Mark - Ready for more Winter!

 

Right on! I wonder how prevalent the gelled heater core problem really is. People should check their auxiliary pumps. Same experience two weeks ago.

 

Glad your heat is fixed.


You didn't mention whether you had the typical heater core failure symptom - cold on driver's side, warm on passenger's. So, what were your symptoms? All of them?


Yes, repairing a clogged heater core is a pain in the butt, but buying and replacing a $300 pump ain't no picnic either. Nor is it good advice without fully exploring the symptoms.


The symptoms make the problem an easy diagnosis. Both sides cool or cold = pump. Only one side cold = core.


The reason you likely didn't see the amount of chatter about the pump is because of the rarity of its failure.


My comments come from a guy who had his doubts until I pulled my core and could see for myself how and (probably) why clogs are common.


Like I said ... glad your heat is back.

 

Ok - So, I just got off the phone with my mechanic here in Vineland, NJ. I took the car in at the beginning of this week because of the lack of heat on the driver's side and I was tired of freezing while my passengers (2 kids) lived the life of luxury in heated comfort.

He said that the Auxiliary Electric Water Pump was bad. He also found a leak on the Coolant Reservoir Tank (mentioned it was typical of Jaguars). And, He is also going to flush out the coolant system. Hopefully, this solves my problem without having to replace the Heater Core and hopefully it's all covered under the extended warranty I purchased.

I will let you know how I make out!

Eric

 

Just for the record, I did have the cold drivers, warm passenger side issue, but just took my auxiliary pump out yesterday and it is shot. The brushes are nearly gone. Definitely not running.


Much easier than the heater core!!!

 

OK, it's not a Jag, but here's what was necessary to replace a leaking heater core in my VW Passat.

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Yuck. At least the dash doesn't have to come out on the Jag...

 

BTW, in my old X300, the brushes in the aux. pump went out. Rather than buying a new pump, I pulled the stub brushes out (what was left of them). I took them to an R/C model store that has brushes for their motors. They found brushes that were almost an exact fit (just had to chamfer one corner), and it worked great. Probably cost me about $5.00 and the time to pull the pump out and put it back (much easier to do in the X300 than the X350. Just FYI if you have pulled your pump and the brushes are bad.

 

I just ordered a replacement auxiliary coolant pump (bosch)...thanks for the tip here, heater isn't as warm (especially on driver side) as it should be. I wanted to do this before I went with any heater core costs.

 

This is a good analysis. The aux pump runs whenever the engine is running and it just wears out and stops turning over time. Its about a 60K miles pump. The X300 uses the same system and it has the same problem. Clogging in the core is only happening if the owner used the wrong coolant and it gelled. If the car always had Dex Cool, that is not likely the problem. The reason that one side is cooler is that with the pump not running, the water flow from the engine pump only is very low and most of the heat that gets there goes to the passenger side then the core is too cool to get the other side hot. Before replacing the core, invest in a mechanics stethoscope and see if the pump is running. Might save some time and money.

 

Guys, Very interested to read all this about the auxiliary coolant pump. How easy is it to remove? Does the whole coolant system need to be drained or can I clamp the 2 pipes? I can barely get my hand on it in my 2006 X350 so I'm thinking at least the header tank has to come off. Also what replacement unit do you suggest. I'm sure I've read somewhere about a Bosch over a Hella. Thanks in advance.

 

Here's one at Amazon http://rcm-na.amazon-adsystem.com/e/...ins=B004JPZ46M

There's also an interesting write up here: JCNA Forums - Jaguar Clubs of North America

I briefly attempted to clamp the two hoses and avoid removing everything, but my arms and hands would need to be the size of my fingers to make that work, so I decided against it.

Here's what I did: (For XJR, this may or may not be the same for XJ8)
- Remove the cover from the bottom of the engine compartment.
- There is a little plastic t-bar handle on the drivers side of the bottom of the radiator. Unscrew it to drain the coolant. It helps if you uncap the header tank.
- Remove the header tank
- Remove whatever other hoses are in your way
- Remove the pump and replace with new or rebuilt pump
- Reverse the process
- Refill the system, then run the car with the heater control on HI until operating temp is reached to make sure coolant reaches all the necessary places.

This whole process took me 1 1/2 hours from pre-jacking of car to turning off the car from driving around the block to test the system.

 

Hunter34, many thanks for this detailed guide. Doesn't sound too much of a job.

 

Hmmm, maybe my pump is out (can't feel it running with the ignition on). When I replaced all my hoses (except that pesky one that goes under the intake manifold--on my list of things to get to), I didn't take the pump out, but did all of the above. However, when I refilled the system, I had a hard time getting any heat. I finally got some out of dumb luck. I happened to park the car in a friend's driveway that is somewhat steep. Whatever air bubble that was blocking the flow finally moved since the engine was tilted up and I got heat (not great on the driver's side). So it looks like I need to pull the pump. Guess I'll just order a new one, and when I get the old one out, if the brushes are gone, I'll get new ones from the R/C model car shop and have it ready in 60k when the new ones go....

 

BTW, it is also at Autopartswarehouse.com: OES Genuine W0133-1656109 Auxiliary Water Pump | Auto Parts Warehouse

But it's cheaper at Amazon and if you have Amazon Prime, free two day shipping rather than ground. Thanks for the Amazon link!

 

Hi All,

So, I got my Jag back from the mechanic yesterday. I had the no heat on driver's side issue. He replaced the Auxiliary Electric Water Pump and a Leaky Reservoir. He also took the time to flush the fluids through the heater core and remove the sediment that had built up. After all that and about $500, the driver's side blows about 70-75% of what the passenger side blows.

The next step, as far as the mechanic is concerned, would be to remove the dash and replace the heater core (day and a half worth of work). My car is still under a 3rd party warranty through May of 2014, so I'm debating whether or not to get it done.

Eric

 

Replaceable brushes. That's what I love about European cars; you can actually disassemble things and make necessary repairs instead of always needing to buy a 'component.'

 

Warranty repair? You lucky dog.

 

I'm looking into whether or not the heater core is a warranty repair. The mechanic is pricing it out for me. The auxiliary water pump and reservoir were covered plus a certain percentage of labor (at a going rate for the area).

It's through warrantys.com - don't know if anyone has any experience with them.

 

It looks like VW started with a piece of carpet and built the car around it.